I had fun playing it yesterday.
I was in first place on the terrorist team while my entire team was bitching about the shield. Every 3 minutes it was "YEA KEEP USING SHIELDS NEWBIE CTS, THEY ARE BANNED IN CAL" and crap like that.
So after being terrorist for a few maps, I went ct and had fun with the shield. It makes an awesome scout. IE, you can have 2 guys with shields run up the front and inform the team of whether there are any dangers. Sort of like in real life if you had a riotsquad.
So, I have mixed feelings on the riot shield. But I love the way steam is built in.